Students redesign Worcester's Elm Park bridge to meet modern standards

Sunday

Jul 20, 2014 at 6:00 AMJul 20, 2014 at 4:13 PM

By Thomas Caywood TELEGRAM & GAZETTE STAFF

WORCESTER — Elm Park has been without its signature red footbridge since last fall, as a team of future civil engineers worked to design a new span that would maintain the iconic look of the old bridge while bringing it up to modern standards of safety and accessibility.

With the design work by Worcester Polytechnic Institute seniors now completed, fabrication of the new bridge by students at Worcester Technical High School is set to begin at the school's large carpentry shop in early September.

Plans call for the replacement bridge to be finished before the winter snows arrive later this year.

"We'll prefabricate everything we can here in-house. Then we'll go down there to the park to construct it on-site," said Kyle J. Brenner, Worcester Tech's director of vocational and career education. "I'm hoping for a November ribbon-cutting, but it's a school, so don't hold me to that."

The new structure will be named the Myra Hiatt Kraft Memorial Bridge in honor of the Worcester native, a philanthropist and late wife of New England Patriots owner Robert Kraft.

The rotting old bridge, built in 1972 based on a historic design dating back to the 19th century, was plucked off its concrete footings by an industrial crane in October and trucked up to Worcester Tech for detailed measurements and condition analysis by the WPI engineering students.

When summer arrived last month and the popular city park filled up with joggers and families again, people wondered what happened to the iconic red bridge that has come to symbolize Elm Park.

"People have been asking where it is and when it'll be back," said Dorothy Hargrove, president of the Park Spirit of Worcester advocacy group. "We all just miss it. It's been such a part of Elm Park for so long. It's really the signature part of the park."

The missing bridge is even depicted on new benches recently installed around the perimeter of the park as part of ongoing renovations.

Since the original footbridge was built in 1877, the span has been replaced a number of times over the years.

While Elm Park without the red bridge may be a bit like Yellowstone National Park without the Old Faithful geyser, the roughly yearlong absence of the bridge this time will pay off for people long excluded from its steeply arched wooden deck — those with disabilities and mobility challenges.

The seven WPI civil engineering students who designed the replacement bridge last year as their senior project could have simply replicated the old bridge without regard for modern accessibility standards, or they could have designed an entirely new structure that was accessible but not historically appropriate to the park.

But the students, who have since graduated and moved on, instead chose a more challenging third approach. They sought to maintain the historic appearance of the bridge while making the new structure fully compliant with the requirements of the Americans with Disabilities Act, said Tahar El-Korchi, head of WPI's Department of Civil, Environmental and Architectural Engineering.

"The goal of the design was to preserve the aesthetics of the old bridges in a structure that met modern engineering and safety standards," he said.

To comply with the ADA's accessibility standards, the roughly 23 percent slope of the old bridge had to be cut down to no more than 8 percent while still maintaining the height of the main arch. If the flatter bridge was any lower than eight feet from the water at the top of its arch, it wouldn't be safe for ice skaters to glide underneath in the winter, Mr. El-Korchi said.

The new span will have to be several feet longer than the old bridge with longer, more gradually sloped earthen approaches on both sides of the wooden structure to accommodate the slope and height requirements. The new design also features a less open handrail design to discourage children from climbing and to prevent them from falling through big gaps in the railing.

Stephen Stolberg, who uses a wheelchair and is a member of the city's Commission on Disability, said he was surprised earlier this year when the WPI engineering students went to City Hall and presented the commission with an ADA compliant design for the replacement bridge.

"I wouldn't have argued with it if they were going to rebuild it as it was. I would have said, 'Well, I've never been able to go over it anyway, so fine,' but when they told us what they were going to do, I was really happy with what they came up with," Mr. Stolberg said. "If someone rolled up to that old bridge with a chair, there's no way you're pushing over it. Or somebody with crutches."

Worcester Tech's Mr. Brenner said former City Manager Michael V. O'Brien approached him early last year to ask if the school's carpentry students were up to the challenge of building a new bridge in Elm Park to replace the partially rotten, unsafe old one.

Having studied civil engineering at WPI himself, Mr. Brenner suggested the city manager approach WPI officials about having engineering students design the bridge as a senior project.

"It's real world for both schools. You've got future engineers working with future tradesmen on this bridge," Mr. Brenner said. "The city saves money, and our students are going to be learning while they're doing it. For years they'll be able to drive by and say, 'I built that.' "

Contact reporter Thomas Caywood at thomas.caywood@telegram.com or follow him on Twitter @ThomasCaywood

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